Generally, a lens focusing device can be used with a variety of handheld devices, such as cell phones, cameras, tablet computers, notebook computers and the like, as well as with various types of webcams, to serve as a lens auto-focusing means during picture shooting.
Up to date, there are many technical means for modifying or improving the shape of a lens holder or an outer case of the lens focusing device, such as lens holder structure and outer case structure designed to enable easier assembling of a lens to the lens holder, or a modification to the octagonal winding structure and the outer case to ensure a wider space for lens assembling.
However, all the currently available lens focusing devices use spring members to maintain the lens holder in an elastically movable state. When a conventional lens focusing device is subjected to the impact of an external force on it, the lens holder elastically movably connected to the spring members tends to collide with other components located therearound and becomes damaged.
Moreover, the lens is generally held in the lens holder by screwing it into the lens holder. Since the lens holder is supported only by two spring members connected to an upper and a lower end thereof to maintain in the movable state, the spring members are possibly damaged when the lens is screwed into the lens holder with an undue turning force and the lens holder is excessively twisted.
In view of the above-mentioned drawbacks, it is desirable to develop a lens focusing device that is impact-resistant and undue-twisting protected.